1) Field of the Invention
The present invention relates to a technology for predicting a failure of a part that is prone to aged deterioration in an electronic device by directly detecting a signal of impending failure of the part.
2) Description of the Related Art
The possibility of a system failure due to breakdown of constituent parts has increased in recent electronic devices, such as an information apparatus or a communication apparatus, because of large scale and high rate of integration of the system. For instance, a blade server that realizes a high-density mounting includes more number of parts, such as several hundred scales of CPUs, than a conventional server, which may cause a higher rate of part failure. Although a method such as a dual operation of a system is employed to avoid the system failure, there still is a system failure occurred due to a complex failure interacted with a latent failure in the system.
Hence, it is extremely important to predict a failure of a part to avoid the system failure, and a technology to predict a part failure using a statistical method has been developed. The failure prediction based on the statistical method compares a result of measurement of operation status of an electronic device using a sensor with an operation model of constituent parts to predict a failure.
The operation model is created based on performance data obtained from each of the parts, and is periodically updated. By compensating a minute disturbance appearing as a noise between the operation model and a result of actual measurement, it is possible to determine whether the result is within an acceptable range or a sign of a coming failure. For instance, in the case of a hard disk device, it is possible to predict a failure by a comparing of a measured response time with a calculated response time from the operation model.
Another technique, as an extension of the statistical method, employs a redundant hardware structure to an electronic circuit or a part of interest, and applies a greater load than that for a normal operation of the circuit to the redundant structure. At the point at which the redundant circuit breaks down it predicts that a breakdown of the circuit may be imminent (for example, see Japanese Patent Laid-Open Publication No. H2-87079 and Japanese Patent Laid-Open Publication No. H7-128384).
However, the accuracy of the statistical method is dependent on a quality of the operation model, and it is difficult to make a model of all operations of a complex semiconductor device with a large-scale. Besides, the accuracy of the statistical method is also dependent on setting a threshold value when determining a difference between an actual operation and the operation model, and it is also extremely difficult to set a proper threshold value.
The method using the redundant circuit is not better than a statistical method, having a problem of a considerable error caused by a variation in the parts, subtle differences in the test environment, etc. Furthermore, regarding running of a system, it is not easy to replace a part of questionable life expectancy in a normally operation status of a circuit of interest.